Where is air filtered and moistened

The conchae swirl the air around to allow the air time to humidify, warm, and be cleaned before it enters the lungs. The cilia, along with mucus produced by seromucous and other glands in the membrane, trap unwanted particles. Finally the filtered, warmed air passes out of the back of the nasal cavities into the nasopharynx, the uppermost part of the pharynx. The paranasal sinuses are four paired, air-filled cavities found inside bones of the skull. These sinuses are named for the skull bones that contain them: frontal, ethmoidal, sphenoidal, and maxillary.

Mucosae line the paranasal sinuses and help to warm and humidify the air we inhale. When air enters the sinuses from the nasal cavities, mucus formed by the muscosae drains into the nasal cavities.

The pharynx, or throat, is shaped like a funnel. The pharynx includes three regions: The nasopharynx is posterior to the nasal cavity and serves only as a passageway for air. The oropharynx lies posterior to the oral cavity and contains the palatine tonsils. Both air and ingested food pass through the oropharynx and through the laryngopharynx below. The laryngopharynx lies posterior to the epiglottis and connects to the larynx superiorly and the esophagus inferiorly. As we breathe, the epiglottis stays up and air passes freely between the laryngopharynx and the larynx.

The larynx connects the lower part of the pharynx, the laryngopharynx, to the trachea. How is oxygen, carbon dioxide, and other waste gases exchanged in the lungs and body tissues? What is the function of the lungs in connection with the circulatory system?

How do the lungs function as excretory organs? What do pulmonary function tests measure? What is pulmonary hypoplasia? Is this condition hereditary? Why are there 3 lobes in the right lung and 2 in the left?

What is the purpose of these lobes? The respiratory tract is the path of air from the nose to the lungs. The lower respiratory tract consists of the Trachea , Bronchi , Bronchioles , and the Lungs. Figure 1.

Click for a larger image. The major respiratory structures span the nasal cavity to the diaphragm. For the sake of convenience, we will divide the respiratory system in to the upper and lower respiratory tracts:.

The upper respiratory tract , can refer to the parts of the respiratory system lying above the sternal angle outside of the thorax , above the vocal folds, or above the cricoid cartilage.

The tract consists of the nasal cavity and paranasal sinuses, the pharynx nasopharynx, oropharynx and laryngopharynx and sometimes includes the larynx. Its primary function is to receive the air from the external environment and filter, warm, and humidify it before it reaches the delicate lungs where gas exchange will occur. Air enters through the nostrils of the nose and is partially filtered by the nose hairs, then flows into the nasal cavity.

The nasal cavity is lined with epithelial tissue, containing blood vessels, which help warm the air; and secrete mucous, which further filters the air. The endothelial lining of the nasal cavity also contains tiny hairlike projections, called cilia.

The cilia serve to transport dust and other foreign particles, trapped in mucous, to the back of the nasal cavity and to the pharynx. There the mucus is either coughed out, or swallowed and digested by powerful stomach acids. After passing through the nasal cavity, the air flows down the pharynx to the larynx.

The lower respiratory tract or lower airway is derived from the developing foregut and consists of the trachea, bronchi primary, secondary and tertiary , bronchioles including terminal and respiratory , and lungs including alveoli.

It also sometimes includes the larynx, which we have done here. This is where gas exchange actually takes place. The larynx plural larynges , colloquially known as the voice box, is an organ in our neck involved in protection of the trachea and sound production. The larynx houses the vocal cords, and is situated just below where the tract of the pharynx splits into the trachea and the esophagus. The larynx contains two important structures: the epiglottis and the vocal cords.

The epiglottis is a flap of cartilage located at the opening to the larynx. During swallowing, the larynx at the epiglottis and at the glottis closes to prevent swallowed material from entering the lungs; the larynx is also pulled upwards to assist this process. Stimulation of the larynx by ingested matter produces a strong cough reflex to protect the lungs. Note: choking occurs when the epiglottis fails to cover the trachea, and food becomes lodged in our windpipe. The vocal cords consist of two folds of connective tissue that stretch and vibrate when air passes through them, causing vocalization.

The length the vocal cords are stretched determines what pitch the sound will have.